1. Field of the Invention
The present application relates generally to the removal of heat from a helicopter gearbox and, more particularly, to use of heat pipes within the gearbox.
2. Description of Related Art
Aircraft drivetrains include various components that produce and transfer power. For example, engines and gearboxes are common components. Such components generate heat and require lubrication. Excessive levels of heat can cause premature failure and create safety risks. Proper lubrication serves to reduce heat production and assist in heat removal from within moving components.
Typically, aircraft use a variety of primary lubrication systems to provide wear protection and control heat transfer within components. Under normal operating conditions, primary lubrication systems provide proper lubrication and heat removal. However, in cases of emergency, primary lubrication systems can fail resulting in excessive wear and failure of components, such as a gearbox or transmission.
Aircraft are generally required to maintain manageable flight operations for selected durations of time if the primary lubrication system fails (zero pressure). One method used to satisfy the requirements of manageable flight during an emergency is to increase the amount of lubricant reserves and increase the weight of the lubricant. Another method is to use a secondary lubrication system to operate when the primary lubrication system fails. Although not commonly used, secondary systems typically provide only sufficient lubricant to lubricate moving parts but fail to adequately remove heat. Both methods increase the overall weight of the aircraft and fail to remove adequate amounts of heat. An improved method of controlling heat transfer from an aircraft is required.
Heat pipes are a device commonly used to transfer heat. Heat pipes are a transfer mechanism that can transport large quantities of heat with a very small difference in temperature between hot and cold interfaces. However, heat pipes are typically used in static environments and experience design limitations from difficulties in moving a working fluid between a condenser end and an evaporator end. External forces, such as gravitational and centrifugal forces, can hinder performance of the heat pipe.
Although great strides have been made in managing heat transfer in aircraft, considerable shortcomings remain.
While the system and method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the application to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the process of the present application as defined by the appended claims.